Abstract
Purpose: :
To examine the effect of intraocularly produced glucagon-like peptide-1 (GLP-1) on the survival rate of retinal ganglion cells in the optic nerve crush model.
Methods: :
Forty-one Sprague-Dawley rats were divided into a study group (21 animals) in which 4 beads with 3000 genetically modified cells to produce GLP-1 were intravitreally implanted into the right eye; a saline control group (n=12) with intravitreal saline injection into the right eye; and a GLP-1 negative bead control group (n=8) in which 4 beads with 3000 cells without GLP-1 production were intravitreally implanted into the right eye. The right optic nerves of all animals were crushed in a standardized manner. After labeling the retinal ganglion cells by injecting 3% fluorogold into the superior colliculus, the animals were sacrificed, and the ganglion cells were counted on retinal flat mounts.
Results: :
The retinal ganglion cell density of the right eyes was significantly higher in the study group (2030±470 cells/mm2) than in the GLP-1 bead negative control group (1390±367 cells/mm2; P=0.001) and than in the saline control group (1734±424 cells/mm2; P=0.07). Correspondingly, the survival rate (ratio of retinal ganglion cell density of right eye / left eye) was significantly higher in the study group (71±19%) than in the GLP-1 bead negative control group (49±14%; P=0.003) and than in the saline control group (57±16%; P=0.03).
Conclusions: :
Glucagon-like peptide-1 produced locally by intravitreally implanted cell beads was associated with a higher survival rate of retinal ganglion cells after an experimental and standardized optic nerve crush in rats.
Keywords: optic nerve • optic disc • neuroprotection